/*
 * Copyright (c) 2016-2017 Andrea Giacomo Baldan
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <sys/time.h>
#include <unistd.h>
#include <pwd.h>
#include <time.h>
#include "util.h"
#include "cluster.h"


#define CHECK_PTR(ptr)                  \
    if (!ptr) {                         \
        perror("No memory available");  \
        return NULL;                    \
    }                                   \
    return ptr;


/* The implementation here was originally done by Gary S. Brown. Slighltly
 * modified by Pete Warden, without any imposition on the reuse of the code.
 */

/* ============================================================= */
/*  COPYRIGHT (C) 1986 Gary S. Brown.  You may use this program, or       */
/*  code or tables extracted from it, as desired without restriction.     */
/*                                                                        */
/*  First, the polynomial itself and its table of feedback terms.  The    */
/*  polynomial is                                                         */
/*  X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0   */
/*                                                                        */
/*  Note that we take it "backwards" and put the highest-order term in    */
/*  the lowest-order bit.  The X^32 term is "implied"; the LSB is the     */
/*  X^31 term, etc.  The X^0 term (usually shown as "+1") results in      */
/*  the MSB being 1.                                                      */
/*                                                                        */
/*  Note that the usual hardware shift register implementation, which     */
/*  is what we're using (we're merely optimizing it by doing eight-bit    */
/*  chunks at a time) shifts bits into the lowest-order term.  In our     */
/*  implementation, that means shifting towards the right.  Why do we     */
/*  do it this way?  Because the calculated CRC must be transmitted in    */
/*  order from highest-order term to lowest-order term.  UARTs transmit   */
/*  characters in order from LSB to MSB.  By storing the CRC this way,    */
/*  we hand it to the UART in the order low-byte to high-byte; the UART   */
/*  sends each low-bit to hight-bit; and the result is transmission bit   */
/*  by bit from highest- to lowest-order term without requiring any bit   */
/*  shuffling on our part.  Reception works similarly.                    */
/*                                                                        */
/*  The feedback terms table consists of 256, 32-bit entries.  Notes:     */
/*                                                                        */
/*      The table can be generated at runtime if desired; code to do so   */
/*      is shown later.  It might not be obvious, but the feedback        */
/*      terms simply represent the results of eight shift/xor opera-      */
/*      tions for all combinations of data and CRC register values.       */
/*                                                                        */
/*      The values must be right-shifted by eight bits by the "updcrc"    */
/*      logic; the shift must be unsigned (bring in zeroes).  On some     */
/*      hardware you could probably optimize the shift in assembler by    */
/*      using byte-swap instructions.                                     */
/*      polynomial $edb88320                                              */
/*                                                                        */
/*  --------------------------------------------------------------------  */

static unsigned long crc32_tab[] = {
    0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
    0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
    0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
    0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
    0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
    0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
    0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
    0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
    0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
    0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
    0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
    0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
    0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
    0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
    0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
    0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
    0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
    0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
    0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
    0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
    0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
    0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
    0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
    0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
    0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
    0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
    0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
    0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
    0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
    0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
    0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
    0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
    0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
    0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
    0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
    0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
    0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
    0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
    0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
    0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
    0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
    0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
    0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
    0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
    0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
    0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
    0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
    0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
    0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
    0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
    0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
    0x2d02ef8dL
};

/* Return a 32-bit CRC of the contents of the buffer. */
unsigned long crc32(const unsigned char *s, unsigned int len) {
    unsigned int i;
    unsigned long crc32val;

    crc32val = 0;
    for (i = 0;  i < len;  i ++) {
        crc32val = crc32_tab[(crc32val ^ s[i]) & 0xff] ^ (crc32val >> 8);
    }
    return crc32val;
}


/*
 * Safely memory allocation function
 */
void *shb_malloc(size_t size) {
    void *ptr = malloc(size);
    CHECK_PTR(ptr);
}


/*
 * Return the current timestamp in milliseconds
 */
long long current_timestamp(void) {
    struct timeval te;
    gettimeofday(&te, NULL);
    long long ms = te.tv_sec * 1000LL + te.tv_usec / 1000;
    return ms;
}

/*
 * trim string, removing leading and trailing spaces
 */
void trim(char *str) {
    int i;
    int begin = 0;
    int end = strlen(str) - 1;

    while (isspace(str[begin]))
        begin++;

    while ((end >= begin) && isspace(str[end]))
        end--;

    // Shift all characters back to the start of the string array.
    for (i = begin; i <= end; i++)
        str[i - begin] = str[i];

    str[i - begin] = '\0'; // Null terminate string.
}

/* auxiliary function to check wether a string is an integer */
int is_integer(const char *s) {
    size_t ln = strlen(s) - 1;
    for(unsigned long i = 0; i < ln; i++)
        if(!isdigit(s[i])) return 0;
    return 1;
}

/* auxiliary function to check wether a string is a floating number */
int is_float(const char *s) {
    if (is_integer(s))
        return 0;
    double dnum;
    if (sscanf(s, "%lf", &dnum) == 0) return 0;
    return 1;
}

/* auxiliary function to convert integer contained inside string into int */
int to_int(const char *s) {
    int len = 0;
    while(isdigit(*s)) {
        len = (len * 10) + (*s - '0');
        s++;
    }
    return len;
}


/* auxiliary function to convert double contained inside a string int a double */
double to_double(const char *s) {
    double dnum;
    if (sscanf(s, "%lf", &dnum) == 1) return dnum;
    return 0.0;
}


/*
 * Define the current node name inside the cluster
 */
const char *node_name(unsigned int len) {

    char *pool = "abcdefghijklmnopqrstwxyz0123456789";
    /* Length of the string */
    int i = 0;

    char *node_name = malloc(len);

    /* build name using random positions in the poll */
    while(len--) {
        node_name[i++] = pool[(rand() % strlen(pool))];
    }

    return node_name;

}


/*
 * Find the home directory, checking if $HOME is set
 */
const char *get_homedir(void) {
    const char *homedir;

    if ((homedir = getenv("HOME")) == NULL) {
        homedir = getpwuid(getuid())->pw_dir;
    }

    return homedir;
}


void s_log(loglevel level, const char *info, ...) {
    /* Print log only if level is the same of the instance loglevel */
    if (level <= instance.log_level) {
        va_list argptr;
        va_start(argptr, info);
        char time_buff[50];
        char prefix[50];
        time_t now = time(0);
        if (1 == instance.verbose) {
            switch(level) {
                case DEBUG:
                    sprintf(prefix, "[DBG]");
                    break;
                case ERR:
                    sprintf(prefix, "\033[1m[ERR]");
                    break;
                case INFO:
                    sprintf(prefix, "[INF]");
                    break;
                default:
                    sprintf(prefix, "[INF]");
                    break;
            }
            strftime(time_buff, 50, "[%Y-%m-%d %H:%M:%S] - ", localtime(&now));
        } else  {
            strftime(prefix, 50, "%Y-%m-%d %H:%M:%S", localtime(&now));
            sprintf(time_buff, " ");
        }
        char content[strlen(prefix) + strlen(info) + strlen(time_buff)];
        memset(content, 0x00, strlen(content));
        strcat(content, prefix);
        strcat(content, time_buff);
        strcat(content, info);
        strcat(content, "\033[0m");
        vfprintf(stdout, content, argptr);
        va_end(argptr);
    }
}


/* Utility function, concat two strings togheter */
char *append_string(const char *str, const char *token) {
    size_t len = strlen(str) + strlen(token);
    char *ret = malloc(len * sizeof(char) + 1);
    *ret = '\0';
    return strcat(strcat(ret, str), token);
}


/* Utility function, remove trailing newline */
void remove_newline(char *str) {
    str[strcspn(str, "\r\n")] = 0;
}


config *create_config(void) {
    config *conf = malloc(sizeof(config));
    conf->log_level = DEBUG;
    conf->name = NULL;
    conf->host = "127.0.0.1";
    conf->port = 8081;
    return conf;
}


void read_config(config *conf, char *filename) {
    FILE *file = fopen(filename, "r");

    if (file == NULL) {
        perror("Couldn't open the configuration file\n");
        free(filename);
        exit(EXIT_FAILURE);
    }

    char line[256];
    int i = 0;

    while (fgets(line, 256, (FILE *) file) != NULL) {

        if (line[0] == '#') {
            i++;
            continue;
        }

        char *cfline;
        cfline = strstr((char *) line, DELIM);
        cfline = strstr((char *) line, DELIM);
        cfline = cfline + strlen(DELIM);

        if (strcmp(line, "loglevel") == 0) {
            if (strcmp(cfline, "debug") == 0)
                conf->log_level = DEBUG;
            else if (strcmp(cfline, "info") == 0)
                conf->log_level = INFO;
            else conf->log_level = ERR;
        } else if (strcmp(line, "nodename") == 0) {
            cfline = cfline + strlen(DELIM);
            conf->name = strdup(cfline);
        } else if (strcmp(line, "host") == 0) {
            conf->host = strdup(cfline);
        } else if (strcmp(line, "port") == 0) {
            conf->port = GETINT(cfline);
        }
    }
    fclose(file);
    DEBUG("Configuration file %s succesfully read", filename);
}
